“The driver struck the mountain lion on a stretch of freeway in the San Francisco suburb of San Bruno and sped away, apparently unaware of what happened. … In the dark or low light, it is possible for motorists to fail to see something in the roadway, even with headlights on.” (http://uk.reuters.com/article/2015/01/03/us-usa-california-mountain-lion-idUKKBN0KC01N20150103)
The cat’s eyes appear not to have worked either.
An experiment “to see how motorists in Brazil treated snakes … [and] if drivers would intentionally run over any of the objects placed in the road … [found that] forty-two fake snakes were intentionally run-over compared to 31 plastic bottles.” (http://news.mongabay.com/2014/0924-mann-fake-snake-roads-tcs.html)
Drivers gunning their vehicles toward plastic water bottles may have felt threatened by the word ‘slake’.